Multiple antennas at the transmitter and receiver increases the capacity in a wireless communication system. By transmitting the same symbol on the transmit antennas, the received signal quality can be increased due the diversity gain. On the other hand, by transmitting different symbols on the transmitting antennas, the data rate of the system can be increased due to multiplexing. In general, one particular mode is not always suitable in a wireless system. Thus, it is often a good practice to switch between diversity and multiplexing.
Conventionally, there are various methods to which to use diversity or multiplexing at any given moment. For example, expected spectral efficiency and/or capacity can be computed at the base station from pilot measurements for each individual communication mode—diversity, adaptation, or multiplexing. Based on the computed efficiency/capacity, it can be decided whether to use diversity or multiplexing.
However, a problem associated with the conventional method is that simply computing the efficiency/capacity at the base station does not fully take into account the environmental conditions that can affect the wireless communication between a UE and the base station.